Adding second Battery to 2003 Tahoe

I have a 2003 Tahoe LT full load auto leveling roof so no DVD. I want to put one in for my 4 year old. Now I had my battery replaced last Dec. and it was a interstate with 600 CCA so I would like to make this the second one and get the right one for my main. Now I will need some sort of setup to make this work. I was a GM salesmen for ten years and sold mostly new but I forget how the 2500 were setup. Any help to do this job on the cheap would be apreciated. Thanks Eric

The job wouldn't be cheap because you will need to upgrade the power cables and ground, alternator, get a 2nd battery relay or solenoid, and it is recommended you have 2 batteries of the exact same age and design.

If you need more power while the truck is running a 2nd battery wont help a bigger alt will. If you really wanna do it right ask @SurrealOne or [MENTION=52280]nakranij[/MENTION] about their dual battery mods. Each runs a different set up Surreal runs two isolated batteries while Nak runs two batteries connected together acting as one much larger battery.

Thanks for thie info and the list. I have a battery that is not the same as I would put in. I was sold a interstate 600CCA. If I understand things That battery is no good. how do I check for the high output Alt. Great pic's, I do plan on some heavy bass units with another amp, plus a DVD for my sick little one (http://hannahdayfoundation.com/) Thanks for the time. Eric

Hi Guy's: I have one more question. Will my highoutput alternator hold up to charging two batterys? And yes I wanted to put in DVD into the headrest for my sick 4 year old ( has Cancer) (https://fundrazr.com/campaigns/8RUPa). So I will start picking up some parts and should take me a few months, but will my Alt. do the job? does anyone know.
Thanks, Eric